Semiconductor storage devices such as a NAND flash memory have been downscaled to increase storage capacities. To realize further downscaling, development of memories using new materials is progressed. For example, new memories such as a ReRAM (Resistance Random Access Memory), a PRAM (Phase-Change RAM) or a PCM (Phase-Change Memory), an iPCM (interfacial PCM), a FeRAM (Ferroelectric Random Access Memory), a FeNAND (Ferroelectric NAND-type memory), and an MRAM (Magnetic Random Access Memory) have been developed.
As downscaling of these new memories has been progressed, variations in characteristics of elements and characteristics of transistors have become large. For example, variations in characteristics of memory elements and variations in threshold voltages of transistors included in a sense amplifier circuit cause erroneous data read. For example, there has been a demand for a circuit configuration that causes no erroneous read even when variations of pair transistors included in a sense amplifier are likely to occur.